Normal Transition and Propagation Characteristics of YBCO Tape

TLDR

YBCO tape offers superior critical current density at high temperatures and fields, making its stability a key concern for future high‑temperature superconductor applications. The study aims to establish a stability criterion for coated conductors by experimentally and numerically investigating the transition to the normal state and normal‑zone propagation in YBCO tapes. YBCO tapes were fabricated by IBAD/PLD, tested at 55–65 K under 5 T while varying heat input and current, and modeled with a finite‑element program that incorporates their I‑V characteristics and examines the effect of Ag‑stabilizer thickness. The FEM model accurately reproduced normal‑state transition and propagation, validating its use, and revealed that Ag‑stabilizer thickness significantly affects the transient thermal behavior of YBCO tapes.

Abstract

YBCO tape is expected to be used in future HTS applications, because it has better J/sub c/ characteristic in high temperatures and in high applied magnetic fields. It is important to consider the stability in superconducting applications. To establish the stability criterion for coated conductors, the characteristics of the transition to the normal state and normal-zone propagation in YBCO sample tapes were examined experimentally and numerically. The YBCO sample tapes were produced by IBAD/PLD method. Measurements were performed as a function of both heat input and operating current for operating temperatures of 55 K, 60 K, and 65 K in a background magnetic field of 5 T. The experimental results were compared with a simulation using a newly developed computer program based on the finite element method (FEM). In the computer program, the I-V characteristics of the YBCO sample tapes were taken into account. The computer program could simulate the normal transition and propagation phenomena and its validity was confirmed. The influence of the thickness of a Ag-stabilizer on the transient thermal behavior of YBCO tapes was examined experimentally and numerically and the results were presented here.